Adobe Systems’ Flash Player is getting closer to appearing on smartphones, with Research in Motion adding its BlackBerry to the list of devices that will run the software. Apple’s elusive iPhone remains out of reach, however.

At its Adobe Max conference in Los Angeles on Monday, Adobe announced that a beta of its new Flash Player 10.1 software will be released by the end of the year for Windows Mobile and the Palm webOS, with betas for Google’s Android and the Symbian platform to follow early next year.

RIM was a last minute addition over the weekend, and it wasn’t immediately clear how soon Flash Player 10.1 for BlackBerrys will appear. Nineteen of the top 20 handset makers have now agreed to carry the software, Adobe said.

Putting Flash on these devices should mean a wider range of content and applications for mobile users, including more games, videos, location-based services and social-networking sites.

The absence of Flash on phones is “one of the great missing parts of the mobile Web,” according to Avi Greengart, a research director with Current Analysis. He expects handset makers and mobile operators to offer the software on devices soon after it comes out of beta, which Adobe says will be in the first half of next year.

In the meantime, developers will be able to download the beta software to develop and test mobile applications and Web sites. A beta of Flash Player 10.1 for Windows, Linux and Macintosh desktops will also be out by the end of the year, Adobe said.

Along with video and other rich content, Flash is used by a lot of Web sites to run advertisements, so its availability on phones should mean more ad-supported services will be made available to mobile users, said Anup Murarka, director of technology strategy and partner development for Adobe’s Flash Platform group.

“A lot of sites depend on advertising to sustain themselves, and they’ve had a tendency to block or restrict mobile access because they couldn’t support it with an advertising model,” he said.

Still, the mobile effort hasn’t been a breeze for Adobe, which has recently fallen behind schedule. In June it said it would release the Flash Player 10 beta in October, to coincide with this week’s Adobe Max conference.

While the Windows Mobile and Palm webOS betas will be out soon, Android and Symbian will be several months late when they arrive next year. Murarka said Android is taking longer because Adobe needs some programming interfaces that will be available with the Eclair release of Android, due later this year.

The iPhone also remains absent from the list of supported devices. “Unfortunately we have no news for you there,” Murarka said. “As we’ve said before, we need additional support and cooperation from Apple to get Flash on the iPhone.”

The iPhone is “a pretty big omission,” Greengart said, but he expects it to arrive eventually. Apple likes to announce such developments at its own events, he noted, and would be unlikely to declare its support for Flash at Adobe Max.

Still, Adobe has come a long way, Greengart said. It has been developing Flash for several phone platforms simultaneously, he noted, which in turn will run hundreds of handset models.

The mobile effort is part of Adobe’s Open Screen Project to provide a common development platform for phones, PCs, netbooks and even televisions. Open Screen is backed by almost 50 device makers, content developers and other partners, Murarka said, up from 16 when it was launched in May last year.

Motorola, Nokia, LG Electronics and Samsung are among the handset makers that have signed up. On Monday, Adobe said it is also working with Nvidia to optimize Flash for its graphics chips in netbooks, and with Qualcomm to get Flash running on its Snapdragon chipset for smartphones.

Having a common runtime that spans different devices should make life easier for developers, but it won’t be a panacea, Murarka acknowledged. Web sites with complex navigational elements won’t translate easily to small screens without additional work.

“But popular video sites and social-networking sites, popular games and sites that use Flash for advertising, those should all work fine,” he said. “It will take a bit of time for developers to evolve their best practices, but the functionality is there with very few exceptions.”

At Adobe Max, Adobe will also show off version 2.0 of its Air runtime environment for desktops, which adds support for peer-to-peer applications and more device peripherals, Murarka said. The software is due out next spring.

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